Is There Really a “Best” Electric Motor?
You’ve probably heard the phrase “Probably the best motor in the world” – a playful twist on Carlsberg’s legendary beer slogan that ran for nearly five decades. But what does beer have to do with electric motors? Absolutely nothing – except to spark an important question: is there truly one “best” motor design?
In recent years, there’s been plenty of buzz around alternative motor topologies – from axial flux to transverse flux, even so-called “raxial” designs – each promising superior power density and other performance gains over the “standard” radial flux motor.
At Equipmake, however, we take a different view: we’re motor topology agnostic. There isn’t one universal “best” motor. Instead, the right motor depends entirely on the specific application. What works perfectly in a lightweight EV might not be optimal for aerospace, marine, or industrial use.
The Fundamentals of Motor Performance
At its core, the maximum torque of any permanent magnet motor depends on the quantity and quality of its active materials – the magnets, electrical steel, and copper or aluminum windings.
The biggest leap in motor performance happened in the early 1980s with the introduction of NdFeB (neodymium-iron-boron) magnets, which revolutionized torque density. Since then, most improvements have been incremental, and topology alone cannot bypass the limits set by these materials.
Another key factor is motor speed. Power is simply torque multiplied by rotational speed, meaning a motor that spins faster achieves higher specific power with the same active mass.
Why Cooling and Efficiency Matter
Peak torque and power make great headlines, but in the real world, what matters most is continuous torque—the level of sustained output the motor can deliver without overheating.
This is where motor cooling systems become critical. At Equipmake, we focus heavily on advanced thermal management, because better cooling increases continuous power without adding cost or weight.
Efficiency also plays a huge role. Higher efficiency means:
- Less heat to manage,
- Improved range in EVs, and
- Better reliability in demanding conditions.
Radial Flux Motors: A Proven Workhorse
While we explore various topologies, our primary focus remains on radial flux (RF) motors in multiple configurations:
- Surface Permanent Magnet (SPM) – including Halbach array and conventional designs,
- Spoke designs, and
- Interior Permanent Magnet (IPM) systems.
Compared to axial flux (AF) motors, RF motors deliver several important advantages:
- Simpler rotor design, enabling higher maximum speeds and excellent power density.
- Single air gap, versus the dual air gaps in AF motors, allowing better flux utilization.
- Easier scalability, where extending the motor length can meet higher torque requirements without major redesigns.
Cost and Performance Balance
IPM motors are particularly attractive because they generate both magnetic torque and reluctance torque, offering higher torque per unit of magnet mass and lower cost compared to pure SPM designs.
For applications chasing peak performance, however, SPM motors—whether radial or axial—remain unmatched, with both topologies delivering similar top-end results.
Choosing the Right Motor
The “best” motor is never about a single specification. It’s about meeting a balanced set of criteria, including:
- Power and torque density,
- Efficiency over the expected duty cycle,
- Cost and scalability in manufacturing, and
- Environmental durability for the intended use case.
This is why Equipmake’s approach remains flexible and application-driven. There’s no one-size-fits-all solution—only the optimal motor for the job.
What’s Next in Motor Innovation
Of course, we’re often asked, “Yes, but what’s the highest power density you can achieve?”
We have exciting developments underway. Our next-generation surface permanent magnet, Halbach-array radial flux motor is designed to set new benchmarks in kW/kg, pushing the limits of power density and efficiency. More details will be revealed soon at CENEX.
And yes—within radial flux designs, debates continue, such as whether hairpin stator windings truly outperform concentrated windings. But that’s a topic for another day… perhaps best discussed over a cold beer. Probably.
Key Takeaways for Engineers and OEMs
- There is no universal “best” motor – only the best fit for a given application.
- Cooling and efficiency are just as critical as peak torque and power.
- Radial flux motors remain highly competitive, with proven scalability and strong cost advantages.
- Continuous innovation in materials, cooling, and winding techniques is pushing performance boundaries across all topologies.